JP4028096B2 - Network system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a network system, and more particularly to a network system capable of effectively performing data communication between a plurality of control devices connected to a LAN (Local Area Network).
[0002]
[Prior art]
In recent years, in a vehicle electronic control system, various control processes necessary for controlling a vehicle drive system such as an internal combustion engine and a transmission have been performed in a distributed manner by a plurality of electronic control devices such as microprocessors. In addition, signals and data are often shared by each electronic control unit, such as the engine speed required for powertrain control and wheel speeds for vehicle control. It has become.
[0003]
FIG. 5 is a block diagram schematically showing an example of a conventional electronically controlled network system in powertrain control.
[0004]
In the figure, reference numeral 1 denotes a network system. The network system 1 is a fuel injection / ignition control device 2 for driving and controlling an injector, an igniter, and an idle speed control step motor, and a transmission control for controlling a solenoid for shifting. It includes a device 3 and a throttle control device 4 that drives and controls a motor that opens and closes a sub-throttle valve provided in the intake system of the engine.
[0005]
These control devices 2 to 4 are connected to each other via a communication line 5 to form a so-called LAN, and data for powertrain control between the control devices 2 to 4 via the communication line 5. By transmitting / receiving these, the vehicle drive system which consists of an engine, an automatic transmission, etc. is controlled.
[0006]
That is, each of the control devices 2 to 4 is configured by a microcomputer having a communication function including a CPU, a ROM, a RAM, and the like, and performs various control processes for powertrain control according to a preset control program. In addition, by performing data communication with another control device via the communication line 5, the vehicle drive system can be controlled in accordance with the engine, the driving state of the vehicle, and the like.
[0007]
The fuel injection / ignition control device 2 is connected to an injector for adjusting the fuel injection amount of the engine, an igniter connected to a spark plug, and an idle speed control step motor, and an air flow for detecting an air flow rate. Meter, main throttle position sensor that detects the opening of the main throttle valve that opens and closes in conjunction with the accelerator pedal, starter switch that detects the starter drive state, idle switch that detects the engine idle state, and engine speed A crank angle sensor for detection, a water temperature sensor for determining the cooling state of the engine, a battery, and the like are connected.
[0008]
The transmission control device 3 is connected with solenoids for shifting, and sensors necessary for calculating a basic control amount of the shift control, for example, a rotation speed sensor for detecting the rotation speed of the torque converter. And a shift switch for detecting the position of the shift lever operated by the driver.
[0009]
The throttle control device 4 is connected to a motor that opens and closes a sub-throttle valve provided separately from the main throttle valve that is opened and closed in conjunction with the accelerator pedal in the intake system of the engine. A sub-throttle position sensor that detects the opening of the throttle valve is connected.
[0010]
Each of the control devices 2 to 4 includes a signal input process for capturing a detection signal from each connected sensor, a data reception process for receiving transmission data from another control device, and a signal input process and a data reception process. A drive control process for driving and controlling each control object based on the obtained data and a data transmission process for transmitting the data obtained by these processes to another control device via the communication line 5 are executed. Yes.
[0011]
Thus, in the network system 1, a communication function is provided in each of the control devices 2 to 4, and a LAN is formed by connecting to the communication line 5, for vehicle control obtained by each of the control devices 2 to 4. By transmitting / receiving data between the control devices 2 to 4, the data is shared between the control devices 2 to 4.
[0012]
For this reason, the control device that detects the data when continuously changing data (throttle opening data, water temperature data, air flow rate data, negative pressure data, etc.) is required on the receiving control device side. These data must be transmitted periodically from the side to the receiving control device side.
[0013]
For example, when the transmission control device 3 controls the solenoids for speed change, the throttle opening data and the water temperature data detected by the fuel injection / ignition control device 2 are required by the transmission control device 3. According to the timer clock of the fuel injection / ignition control device 2, throttle opening data, water temperature data, etc. are periodically transmitted from the fuel injection / ignition control device 2 to the transmission control device 3 (for example, throttle In the case of opening degree data, it is transmitted in a cycle of 2 ms, and in the case of water temperature data, it is transmitted in a cycle of 64 ms).
[0014]
In addition, data that does not change continuously (for example, shift lever position data detected by a shift switch), that is, data that does not need to be transmitted periodically (data that is transmitted aperiodically) is also used as a communication line. 5 to communicate. Such data is transmitted aperiodically with changes in the vehicle state or the like.
[0015]
As described above, when a LAN is formed and data communication is performed on the network, for example, at substantially the same time as when the water temperature data is transmitted from the fuel injection / ignition control device 2 (strictly speaking, the fuel injection -Some data may be transmitted from the transmission control device 3 before the data transmitted by the ignition control device 2 arrives at the transmission control device 3). Then, the certain data and the water temperature data collide somewhere between the fuel injection / ignition control device 2 and the transmission control device 3.
[0016]
[Problems to be solved by the invention]
When a data collision occurs on the network, each data is destroyed, and it is necessary to retransmit these data from each control device. At this time, in order to prevent the collision from occurring repeatedly, the data is retransmitted after a predetermined time elapses when the collision occurs.
[0017]
Therefore, when the collision occurs, there is a case where a large delay occurs in data transmission, and there is a possibility that appropriate control of the device cannot be performed in each control device.
[0018]
JP-A-9-247192 discloses a communication system that detects the number of collisions per unit time on a network and adjusts the data transmission timing when the number of collisions exceeds a predetermined number. Such a method has the following problems.
[0019]
(1) When there is data periodically transmitted from each of the two control devices, if the transmission timing of these data overlaps (that is, they are transmitted at approximately the same time), these data collide each time. (Crashes occur chronically). In such a case, it is desirable to adjust the transmission timing in order to reduce the number of collisions.
[0020]
However, in the above situation, although the collision occurs chronically, the number of collisions per unit time is maintained at a certain number of times. Therefore, in the communication method, the situation is a target for adjusting the transmission timing. It will not be. Therefore, since the transmission timing is not adjusted, the number of collisions of these data cannot be reduced.
[0021]
{Circle around (2)} Due to the influence of non-periodically transmitted data or the like, the collision may happen to the data that should not cause the collision during normal times. In such a case, the number of collisions often increases instantaneously in many cases, so the number of collisions per unit time also naturally increases. In the above communication method, the above situation adjusts the transmission timing. The transmission timing is adjusted.
[0022]
However, even if the transmission timing is adjusted based on the collision that occurred only temporarily, that is, the collision that happened due to the influence of non-periodically transmitted data, etc., the number of subsequent data collisions was reduced. It is clear that there is no basis for this. Conversely, there is a possibility of adversely affecting data that could be transmitted smoothly (without collision).
[0023]
The present invention has been made in view of the above problems, and reduces the number of collisions of periodically transmitted data in a network system in which a plurality of control devices are connected and data is communicated between these control devices. Therefore, an object of the present invention is to provide a network system capable of effectively communicating data.
[0024]
[Means for solving the problems and effects thereof]
  In order to achieve the above object, a network system (1) according to the present invention is connected to a plurality of control devices, and data is communicated between these control devices.IsIn this network system, it transmits to each of these control devices from its own device.YouFirst judging means for judging whether or not a collision has occurred in the network, and second judging means for judging whether or not the collision has occurred chronically based on the judgment result And a first adjusting means for adjusting a transmission timing of data periodically transmitted from the own device when it is determined that the collision occurs chronically.The first calculation means for obtaining a transmission delay time by subtracting the transmission time normally required for the data from the difference between the transmission completion time and the transmission start time of the data in which the collision has occurred. And a second calculating means for obtaining an adjustment amount of the transmission timing based on the transmission delay time, wherein the first adjusting means adjusts the transmission timing according to the adjustment amount.It is characterized by having.
[0025]
  According to the network system (1), if a collision on the network occurs chronically, it is considered that the transmission timings of data periodically transmitted between a plurality of control devices overlap. In this case, since the transmission timing is adjusted, the number of collisions of data transmitted periodically can be reduced, and data can be communicated effectively.
  Furthermore, according to the network system (1), the transmission timing is adjusted according to the adjustment amount obtained based on the actually generated transmission delay time, that is, based on past collision experiences. Thus, the number of collisions of data transmitted more appropriately and periodically can be reduced.
[0026]
  Further, the network system (2) according to the present invention is a network system in which a plurality of control devices are connected and data is communicated between these control devices. First determination means for determining whether or not a collision has occurred, and third determination means for determining whether or not the collision has occurred continuously over a predetermined number of times based on the determination result And a second adjusting means for adjusting a transmission timing of data periodically transmitted from the own device when it is determined that the collision continuously occurs exceeding the predetermined number of times,A first calculating means for obtaining a transmission delay time by subtracting a transmission time normally required for the data from a difference between a transmission completion time and a transmission start time of the data in which the collision has occurred; And a second calculation means for obtaining an adjustment amount of the transmission timing based on the transmission delay time, and the second adjustment means adjusts the transmission timing according to the adjustment amount.It is characterized by having.
[0027]
According to the network system (2), when the collisions on the network occur continuously exceeding the predetermined number of times, the transmission timings of the data periodically transmitted between the plurality of control devices overlap. In such a case, since the transmission timing is adjusted, the number of collisions of periodically transmitted data can be reduced, and data communication can be performed effectively.
[0029]
  further,The above network system (2), The transmission timing is adjusted according to the adjustment amount obtained based on the actually generated transmission delay time, that is, based on the experience of past collisions. The number of collisions of transmitted data can be reduced.
[0030]
  The network system according to the present invention (3) The above network system (1) or (2), The second calculation means adjusts the newly determined transmission delay time when the newly determined transmission delay time is significantly different from the previously determined transmission delay time. It is not included in the quantity calculation element.
[0031]
  The above network system (3According to the above, if the difference between the newly obtained transmission delay time and the previously obtained transmission delay time is large, the newly obtained transmission delay time is determined as the non-periodically transmitted data, etc. Considering that the transmission delay time is temporarily increased due to the collision caused by the influence, such a transmission delay time is not added to the calculation element of the adjustment amount, thereby calculating the more appropriate adjustment amount. can do.
[0032]
  The network system according to the present invention (4) The above network system (Any of 1) to (3)In each of these control devices, storage means for storing and saving the adjustment amount even after the power of the device is turned off, and when the device power is turned on, the start timing of the timer clock of the device is set to the adjustment amount. And a third adjusting means for adjusting accordingly.
[0033]
  The above network system (4), Since the adjustment amount is stored and saved, the transmission timing can be adjusted in the same manner as before power-off, and the number of collisions of data transmitted periodically can be reduced. Moreover, an appropriate periodic schedule can be learned by repeating the power-on several times. Further, since the start timing of the timer clock itself is adjusted, control processing synchronized with transmission can also be adjusted.
[0034]
  The network system according to the present invention (5) Is the network system (1) to (4), Each of the control devices includes a fourth adjustment unit that adjusts the timing of the control process accompanying the transmission of the transmission data in addition to the adjustment of the transmission timing.
[0035]
  The above network system (5), It is possible to eliminate the difference between the data transmission timing and the timing of the control processing accompanying the transmission.
[0036]
  The network system according to the present invention (6) The above network system (5), The fourth adjusting means does not perform the adjustment exceeding a predetermined amount at a time.
[0037]
  The above network system (6), If the timing of the control process is suddenly adjusted in the same manner as the data transmission timing is adjusted, there is a possibility that the control process may malfunction. By making the timing adjustment gradually, it is possible to prevent the occurrence of the above problems.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a network system according to the present invention will be described below with reference to the drawings. Note that the schematic diagram in the network system according to the embodiment (1) of the present invention is substantially the same as the configuration shown in FIG. I will do it.
[0039]
As described in the section of the prior art, in the network system 1, each control device 2 to 4 is provided with a communication function and connected to the communication line 5 to form a LAN, which is obtained by each control device 2 to 4. By transmitting / receiving data for vehicle control between the control devices 2 to 4, the data is shared between the control devices 2 to 4. In the network system according to the embodiment (1), when transmitting such data, the transmission timing is adjusted in order to reduce the collision on the network.
[0040]
Hereinafter, a series of processes relating to data periodically detected and transmitted by any one of the control devices 2 to 4 will be described based on the flowcharts shown in FIGS. 1, 2, and 3. explain.
[0041]
First, FIG. 1 shows the operation of the microcomputer provided in any one of the control devices 2 to 4 of the network system according to the embodiment (1) when a transmission interrupt of periodically transmitted data occurs. This will be described based on the flowchart shown.
[0042]
If there is a transmission interrupt for data that is transmitted periodically, first the transmission timing adjustment amount T_adj Is determined to be 0 (S1). Adjustment amount T_adj The method of calculating will be described in detail later (see FIG. 2).
[0043]
Adjustment amount T_adj If it is determined that is not 0, the adjustment amount T_dly Adjustment amount T_dly Adjustment amount T_adj Is updated to a value obtained by adding (S2), and the updated adjustment amount T is updated._dly Is stored in a RAM that can be stored and stored even after the power of the control device is turned off (S3)._adj Are set to 0 (S4), and the process proceeds to Step 5.
On the other hand, the adjustment amount T_adj If it is determined that is 0, Steps 2 to 4 are skipped and the process proceeds to Step 5.
[0044]
In step 5, the transmission timing based on the periodic schedule is adjusted with the adjustment amount T._dly Then, in step 6, transmission processing is performed such that transmission data is transmitted by adding a transmission destination address and a transmission source address._s Capture.
[0045]
Next, the operation of the microcomputer provided in any one of the control devices 2 to 4 when a transmission completion interrupt of periodically transmitted data occurs will be described based on the flowchart shown in FIG.
[0046]
If there is an interrupt of a signal notifying the completion of transmission of periodically transmitted data, first, the transmission completion time t_e (S11), transmission completion time t_e And transmission start time t_s The value obtained by subtracting the transmission time α (≈data length) normally required from the data is defined as a transmission delay time Δt (S12), and it is determined whether or not the transmission delay time Δt is substantially zero. (S13). This determination determines whether there is a collision on the network, and corresponds to the operation process of the first determination means.
[0047]
If it is not 0, that is, if it is determined that there is a collision, 1 is added to the counter C (S14), and then the transmission delay time Δt obtained last time from the transmission delay time Δt obtained this time._s It is determined whether or not the value obtained by subtracting is over a predetermined value β (S15). The determination here is to determine whether or not the collision has occurred only temporarily, that is, whether or not the collision has occurred due to the influence of data transmitted non-periodically.
[0048]
If it is determined that the collision exceeds the predetermined value β, that is, the collision has occurred temporarily, step 16 is skipped and the process proceeds to step 17. On the other hand, if it is determined that the predetermined value β is not exceeded, the adjustment amount ΔT is updated as an average value of the adjustment amount ΔT obtained in the past and the transmission delay time Δt obtained this time (S16), and the process proceeds to step 17. Move.
In step 17, the transmission delay time obtained last time (Δt_s ← Δt), and then move to step 21.
[0049]
On the other hand, if it is almost 0 (including 0), that is, it is determined that there is no collision, 1 is subtracted from the counter C (S18), and then it is determined whether the counter C is less than 0 (S19). If it is determined that it is less than 0, the counter C is set to 0 (S20), and the process proceeds to step 21. On the other hand, if it is determined that it is equal to or greater than 0, step 20 is skipped and step 21 is entered.
[0050]
In step 21, the counter C is set to a predetermined number γ.₁ It is determined whether or not it exceeds. The determination here determines whether or not a collision on the network has occurred chronically, and corresponds to the operation process of the second determination means.
[0051]
Counter C is a predetermined number of times γ₁ Is exceeded, that is, if the collision has occurred chronically, the adjustment amount ΔT is changed to the adjustment amount T._adj (S22). On the other hand, the counter C is a predetermined number of times γ₁ If it is determined that it does not exceed, step 22 is skipped and the operation is terminated.
[0052]
Next, the operation of the microcomputer equipped in one of the control devices 2 to 4 when the power of each control device 2 to 4 is turned on will be described based on the flowchart shown in FIG.
[0053]
When the power is turned on, the adjustment amount T stored in RAM first_dly (See step 3 in FIG. 1) and the adjustment amount T ′_dly (S41), adjustment amount T '_dly (← T ’_dly + T_dly ) Is updated (S42), and the start timing of the timer clock is adjusted by the adjustment amount T '._dly (S43) and start the timer clock (S44). Then, the adjustment amount T ′_dly Is stored in a RAM that can be stored and saved even after the power is turned off (S45)._dly Is set to 0 (S46).
[0054]
According to the network system according to the above embodiment (1), the transmission timings of data periodically transmitted between a plurality of control devices overlap if a network collision occurs chronically. In such a case, since the transmission timing is adjusted, the number of collisions of data transmitted periodically can be reduced, and data communication can be performed effectively.
[0055]
In addition, since the transmission timing is adjusted according to the adjustment amount ΔT obtained based on the transmission delay time Δt, that is, based on past collision experiences, the number of collisions of data transmitted more appropriately and periodically Can be reduced.
[0056]
Also, the newly determined transmission delay time Δt and the previously determined transmission delay time Δt_s If the difference between the transmission delay time and the transmission delay time is large, it is considered that the transmission delay time Δt is temporarily increased due to a collision caused by the influence of data transmitted aperiodically, and such a transmission delay time. By not adding the time Δt to the calculation element of the adjustment amount ΔT, a more appropriate adjustment amount ΔT can be calculated.
[0057]
Also, the adjustment amount T_dly Is stored and saved, the transmission timing is adjusted in the same manner as before power-off, and the number of collisions of data transmitted periodically can be reduced. Moreover, an appropriate periodic schedule can be learned by repeating the power-on several times. Further, since the start timing of the timer clock itself is adjusted, control processing synchronized with transmission can also be adjusted.
[0058]
Next, the network system according to Embodiment (2) will be described. The network system according to the embodiment (2) is different from the network system according to the above embodiment (1) only in the criterion for adjusting the transmission timing, and only that part will be described below.
[0059]
The operation of the microcomputer provided in the control device when a transmission completion interrupt for periodically transmitted data occurs will be described based on the flowchart shown in FIG.
[0060]
If there is an interrupt of a signal notifying the completion of transmission of periodically transmitted data, first, the transmission completion time t_e (S51), transmission completion time t_e And transmission start time t_s A value obtained by subtracting the transmission time α (≈data length) that is normally required from the data is defined as a transmission delay time Δt (S52), and it is determined whether or not the transmission delay time Δt is substantially zero. (S53). This determination determines whether there is a collision on the network, and corresponds to the operation process of the first determination means.
[0061]
If it is not 0, that is, it is determined that there is a collision, 1 is added to the counter C (S54), and the transmission delay time Δt obtained last time from the transmission delay time Δt obtained next time._s It is determined whether or not the value obtained by subtracting is over a predetermined value β (S55). The determination here is to determine whether or not the collision has occurred only temporarily, that is, whether or not the collision has occurred due to the influence of data transmitted non-periodically.
[0062]
If it is determined that the collision exceeds the predetermined value β, that is, the collision has occurred temporarily, step 56 is skipped and the process proceeds to step 57. On the other hand, if it is determined that the predetermined value β is not exceeded, the adjustment amount ΔT is updated as an average value of the adjustment amount ΔT obtained in the past and the transmission delay time Δt obtained this time (S56), and the process proceeds to step 57.
In step 57, the previously obtained transmission delay time is updated (Δt_s ← Δt), and go to step 59.
[0063]
On the other hand, if it is almost 0 (including 0), that is, it is determined that there is no collision, the counter C is set to 0 (S58), and the process proceeds to step 59.
[0064]
In step 59, the counter C is incremented by a predetermined number γ.₂ It is determined whether or not it exceeds. The determination here determines whether or not network collisions occur continuously, and corresponds to the operation process of the third determination means.
[0065]
Counter C is a predetermined number of times γ₂ Is exceeded, that is, it is determined that the collision occurs continuously, the adjustment amount ΔT is changed to the adjustment amount T._adj (S60). On the other hand, the counter C is a predetermined number of times γ₂ If it is determined that it does not exceed, step 60 is skipped and the operation is terminated.
[0066]
According to the network system according to the above embodiment (2), the network collision occurs a predetermined number of times γ.₂ If it occurs continuously over the range, it is considered that the transmission timing of data periodically transmitted between a plurality of control devices overlaps, and in such a case, the transmission timing is adjusted. The number of collisions of periodically transmitted data can be reduced, and data can be communicated effectively.
[0067]
Further, in the network system according to the embodiment (1) or (2), the control device is equipped with an adjustment unit that adjusts the timing of control processing accompanying transmission of transmission data in addition to the adjustment of the transmission timing. Accordingly, it is possible to eliminate a difference between the data transmission timing and the timing of the control processing accompanying the transmission. Further, by gradually adjusting the timing of the control process, it is possible to prevent a problem from occurring in the control process.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an operation of a microcomputer provided in a control device of a network system according to an embodiment (1) of the present invention when a transmission interrupt of periodically transmitted data occurs. .
FIG. 2 is a flowchart showing an operation of a microcomputer provided in the control device of the network system according to the embodiment (1) when a transmission completion interrupt of periodically transmitted data occurs.
FIG. 3 is a flowchart showing the operation of the microcomputer provided in the control device of the network system according to the embodiment (1) when the control device is powered on.
FIG. 4 is a flowchart showing an operation of a microcomputer provided in the control device of the network system according to the embodiment (2) when a transmission completion interrupt of periodically transmitted data occurs.
FIG. 5 is a block diagram schematically showing an example of a conventional electronically controlled network system in powertrain control.
[Explanation of symbols]
1 Electronic control system
2 Fuel injection / ignition control device
3 Transmission control device
4 Throttle control device
5 communication lines

Claims (6)

In a network system in which a plurality of control devices are connected and data is communicated between these control devices,
A first judging means for judging whether or not a collision on the network has occurred in the data transmitted from the own device to each of the control devices;
Second determination means for determining whether or not the collision occurs chronically based on the determination result;
A first adjusting means for adjusting a transmission timing of data periodically transmitted from the own device when it is determined that the collision occurs chronically ;
A first calculating means for obtaining a transmission delay time by subtracting a transmission time normally required for the data from a difference between a transmission completion time and a transmission start time of the data in which the collision has occurred; ,
Second calculating means for obtaining an adjustment amount of the transmission timing based on the transmission delay time;
The network system, wherein the first adjusting means adjusts the transmission timing according to the adjustment amount . In a network system in which a plurality of control devices are connected and data is communicated between these control devices,
A first judging means for judging whether or not a collision on the network has occurred in the data transmitted from the own device to each of the control devices;
Based on the determination result, a third determination means for determining whether or not the collision has occurred continuously over a predetermined number of times;
A second adjusting means for adjusting a transmission timing of data periodically transmitted from the own device when it is determined that the collision has occurred continuously beyond the predetermined number of times;
A first calculating means for obtaining a transmission delay time by subtracting a transmission time normally required for the data from a difference between a transmission completion time and a transmission start time of the data in which the collision has occurred; ,
Second calculating means for obtaining an adjustment amount of the transmission timing based on the transmission delay time;
The network system, wherein the second adjusting means adjusts the transmission timing according to the adjustment amount . When the newly determined transmission delay time is significantly different from the previously determined transmission delay time, the second calculation means calculates the newly determined transmission delay time as the adjustment amount. 3. The network system according to claim 1 , wherein the network system is not included in an element. In each of these control devices, storage means for storing and storing the adjustment amount even after the power of the device is turned off,
The apparatus according to any one of claims 1 to 3, further comprising third adjusting means for adjusting a start timing of the timer clock of the device according to the adjustment amount when the device is powered on. The network system described. The respective control device, wherein in addition to the adjustment of the transmission timing, any one of claims 1-4, characterized in that it comprises a fourth adjusting means for adjusting the timing of the control processing accompanying the transmission of the transmission data The network system described in the section. 6. The network system according to claim 5, wherein the fourth adjustment means does not perform the adjustment exceeding a predetermined amount at a time.

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